The use of ribbed pipe or conduit in building construction is very widespread. Normally, such ribs are on metal pipe or conduit in a spiraling continuous rib. However, plastic conduit is now being manufactured with discrete separate ribs. In many instances lengths of the pipe are joined together by couplings in end to end relation, or are coupled to junction boxes, and contain electrical wiring. It is a frequent practice to assemble such conduit components on steel reinforcing bars and then pour a layer of concrete to encase the conduit. Certain prior art arrangements do not afford sufficient integrity to the system, being subject to unintentional disconnection when accidentally trodden upon, and endangering the integrity of the system.
A further problem encountered with certain types of prior art couplings and end fittings is the possibility of concrete leakage under the described encasing situations, whereby the internal integrity of the conduit system is compromised.
Certain aspects of different types of the prior art are exemplified in the following listed U.S. Pats. Nos.:
______________________________________ 3,785,682 Schaller et al January 1974; 3,899,198 Maroschak August 1975; 4,084,844 Abner April 1978; 4,248,459 Pate et al February 1981; 4,368,904 Lanz January 1983; 4,441,745 Nicholas April 1984; 4,168,091 Boomgarden September 1979; 4,443,031 Borsh April 1984; 4,470,622 Pate et al September 1984; 4,247,136 Fouss et al January 1981; 4,575,132 Nattel March 1986; 4,575,133 Nattel March 1986; 4,067,534 Frey January 1978. ______________________________________